Fasteners for securing an externally threaded member such as a screw through an opening in a panel or other object have characteristically featured a pair of opposed resilient arms overhanging an aperture through which the screw is received and whose respective free-ends are adapted to threadingly engage the threads on opposite sides of the threaded member and enable it to advance rotationally therethrough. Examples of such fasteners are disclosed in U.S. Pat. Nos. 2,288,710; 2,771,113; 4,200,027; and 4,508,477, the disclosures of which are incorporated herein by reference. In other instances, the aperture is surrounded by a projection ending in a helical edge that is adapted to threadingly engage the threads of the threaded member of which examples are disclosed in U.S. Pat. Nos. 2,117,775; 3,570,361; 3,362,278; and 4,201,111, the disclosures of which are incorporated herein by reference.
Heretofore, those fasteners featuring a helical thread engaging edge have characteristically been separately sized for each screw requiring a particular fastener for each screw size and, in addition, have often employed a pair of overhanging opposed resilient arms that engage and impart a force against the threaded member to prevent it from loosening from the fastener.
Fasteners of the aforementioned type, featuring a pair of opposed resilient arms whose free-ends threadingly engage the threads of the threaded member to provide the securement therebetween, are necessarily spread apart as the thread diameter increases which in turn diminishes the included angle between the rotational axis of the threaded member and the arms and accordingly diminishes the radially inwardly directed force component they exert against the threads to prevent the threaded member from loosening.
The fastener of the present invention overcomes the shortcomings of the prior art fasteners hereinbefore described by being able to secure any selected one of a plurality of externally threaded members having thread diameters ranging from a minimum to a maximum over a broad range whilst imparting a force thereagainst whose direction is substantially consistent in being directed radially inwardly and whose value increases as the thread diameter increases from a minimum to a maximum.